“Sorry,” said Federer, his eyes welling up. “I hope he would be proud. I guess he didn't want me to be a wasted talent so I guess it was somewhat of a wake-up call for me when he passed away and I really started to train hard.”

The year after Carter died, in 2003, Federer won Wimbledon, the first of his 20 Slam titles. “Peter was really a really important person in my life because I think if I can say thank you for my technique today, it's to Peter,” Federer said.